The present invention relates to a circuit board holding apparatus which is provided for a component mounting apparatus for mounting, for example, electronic components onto a circuit board such as a printed board and executes holding and releasing the hold of the circuit board and to a circuit board, hold releasing method executed by the circuit board holding apparatus.
In a component mounting apparatus for mounting electronic components onto a printed board, a portion which executes securing and holding of the printed board in the stage of mounting the electronic components is constructed as follows. That is, as shown in FIGS. 7 and 8, a circuit board holding apparatus 1 for securing and holding a printed board 2 is provided on an X-Y table for moving the printed board 2 in X- and Y-directions. On the circuit board holding apparatus 1 is fixed a pair of stationary members 13 which extend parallel to the X-direction and have an approximately inverted L-like sectional shape. Also provided are a pair of movable members 14 which extend in the X-direction along inner side surfaces 13a of the stationary members 13 and oppose each other at both the stationary members 13 and slide in a Z-direction between a board gripping position 20 and a board releasing position 21 while being guided along the inner side surfaces 13a. In such a circuit board holding apparatus 1, the printed board 2 is conveyed into a region between the stationary members 13. Then, by moving upward both of the movable members 14 into the board gripping position 20 by means of drive units 15 having, for example, an air cylinder, the edge portions 2a of the printed board 2 extending in the X-direction are gripped by board contact surfaces 13b of the stationary members 13 and board contact surfaces 14b of the movable members 14, so that the printed board 2 is secured to the circuit board holding apparatus 1.
The X-Y table on which the printed board 2 is secured in this manner is moved into a specified position in the X- and Y-directions, and mounting of electronic components onto the printed board 2 is executed by an electronic component mounting unit 3. After the operation of mounting specified electronic components onto the printed board 2 is completed, the drive units 15 are operated to move the movable members 14 downward to the board releasing position 21 as shown in FIG. 9, where the gripping of the printed board 2 is released and the printed board 2 is conveyed to the next process.
However, in the aforementioned circuit board holding apparatus 1, there may occur a phenomenon that the printed board 2 sticks to the stationary members 13 as shown in FIG. 10 depending on the surface conditions of the printed board 2 in spite of the fact that the movable members 14 have been moved down to the board releasing position 21. That is, it is sometimes the case where a rubber material is attached or coated on the board contact surface 13b of the stationary member 13 and the board contact surface 14b of the movable member 14 for the purpose of increasing the frictional force between the stationary member 13 and the movable member 14 and the printed board 2 so that the displacement of the printed board 2 should not occur in the X-direction in the state in which the printed board 2 is gripped. Therefore, in the case where a flux is coated on the front and rear surfaces of the printed board 2 or in a similar case, the aforementioned rubber material and the front and rear surfaces of the printed board 2 might stick to each other due to the aforementioned gripping operation. After such a stuck state has occurred, the printed board 2 falls onto the movable members 14 side by its own gravity. However, this disadvantageously causes a state in which the positions of the electronic components mounted on the printed board 2 are displaced by the falling of the printed board 2, a state in which the printed board 2 cannot be conveyed to the next process or a similar state.
The present invention has been developed to solve the above issue and provide a circuit board holding apparatus which prevents the occurrence of displacement of the mounted electronic components and the state in which the printed board cannot be conveyed to the next process after the electronic components have been mounted onto the circuit board, and a circuit board hold releasing method to be executed by the circuit board holding apparatus.
In accomplishing these and other aspects, according to a first aspect of the present invention, there is provided a circuit board holding apparatus for holding a circuit board by gripping a pair of opposed edge portions of a circuit board, comprising:
stationary members which are arranged opposite the edge portions and contact a front surface of the circuit board;
movable members which contact a rear surface of the circuit board and grip each of the edge portions of the circuit board between the movable member and the stationary member in a direction of thickness of the circuit board by moving into a board gripping position, the movable members moving in the direction of thickness of the circuit board between the board gripping position and a board releasing position; and
a separation mechanism for forcibly separating the circuit board from the stationary members when the movable members move from the board gripping position to the board releasing position for releasing the hold of the circuit board.
According to a second aspect of the present invention, there is provided a circuit board holding apparatus as defined in the first aspect, wherein the separation mechanism is a pressing member which is mounted to the stationary member and puts the circuit board into pressure contact with the movable member.
According to a third aspect of the present invention, there is provided a circuit board holding apparatus as defined in the second aspect, wherein, when the front and rear surfaces of the circuit board are located upward and downward and the movable member moves in a vertical direction, the pressing member is an elastic member having one end portion to be fixed to the stationary member and the other end portion which is to contact the front surface of the circuit board and presses the circuit board against the movable member.
According to a fourth aspect of the present invention, there is provided a circuit board holding apparatus as defined in the first aspect, wherein the separation mechanism is a suction unit having a suction section which is arranged on the rear surface side of the circuit board and attracts by suction the rear surface of the circuit board, and a drive unit which moves the suction section in a direction in which the movable member moves together with the moving of the movable member.
According to a fifth aspect of the present invention, there is provided a circuit board holding apparatus as defined in the fourth aspect, further comprising a control unit which controls the start of the moving of the movable member from the board gripping position into the board releasing position, the start of the sucking of the circuit board by the suction unit, and the moving of the suction unit by means of the drive unit.
According to a sixth aspect of the present invention, there is provided a circuit board hold releasing method to be executed by a circuit board holding apparatus which grips a pair of opposed edge portions of a circuit board in a direction of thickness of the circuit board by means of a stationary member and a movable member moving between a board gripping position and a board releasing position, thereby holding the circuit board, comprising:
moving the movable member into the board releasing position in a process of releasing the gripping of the circuit board; and
making the circuit board contact the movable member together with the moving of the movable member toward the board releasing position side.